var exec = require('child_process').exec;

exec('ffmpeg.exe -i 123.mp3 -ar 8000 -ac 1 123.amr', function (err, stdout, stderr) {
  if (err) {
    // reject(new Error('error:' + stderr));
    console.log(err);
  } else {
    // resolve(outputDir + '/' + _outputName + '.mp3');
    console.log('成功');
  }
});